Solid materials synthesized from particles having a grain size in the nanometer range are the subject of active development due to their unique properties. For example, nanometer-scale crystals have the potential of improving the processing and performance characteristics of ceramics, composite polymers, and inter-metallic materials, along with systems, and media incorporating such materials. Products and materials with nanometer-scale crystallites are formed from nanometer-scale particles in processes that entail the steps of forming the particles of the desired chemistry and size scale, combining the particles, and then densifying the particles. Traditional metallurgical techniques such as casting, hot rolling, isostatic pressing, and powder metallurgy have been used to combine the particles.
In the case of aluminum, high strength alloys may be created by cryogenic milling and consolidating aluminum particles. The aluminum particles are then mechanically alloyed using a cryogenic milling operation involving liquid nitrogen in a high-energy ball mill. The powder can subsequently be canned, degassed, and subjected to hot isostatic pressing [“HIP”] to form a fully dense billet. The billet ductility at cryogenic temperatures ranges from about 1% to about 5%. Tensile testing and metallurgical evaluation are routinely carried out as methods for tracking the effectiveness of these processes. Accordingly, cryogenic milling is a technique that might be increasingly important to produce alloys of certain metals that are amenable to this type of processing and that have special or custom properties.
There is an industrial need for high strength copper alloys for certain applications, and this need is often fulfilled with use of a copper-beryllium alloy. While this alloy is useful, some concern has been expressed that beryllium may be a health hazard. Specifically, it is theorized that beryllium at the surface of the alloy may form an oxide that could become airborne. When airborne, the beryllium oxide could be a health hazard to at least some people who are exposed to breathing the oxide. As a consequence, there is a need to develop a high strength copper alloy with a metal other than beryllium that does not raise concerns. In addition, it is desirable that the alloy include those desirable physical properties such as strength that have made copper-beryllium desirable, and if possible provide benefits or advantages that were not present in copper-beryllium. For example, it would be advantageous if the ductility, toughness, fracture resistance, corrosion resistance, fatigue resistance and other physical properties of the alloy could be tailored by balancing the alloy composition. In addition, the alloy should not require extensive or expensive post-treatment. Furthermore, other desirable features and characteristics of the embodiments will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.